Community tank fry identity

So here’s the scenario. You have a community tank containing several species, at least two of which you’re certain you have a breeding pair. You’re doing routine tank maintenance and you stumble upon some really small fry. They’re much too small to identify the species. So how do you know what you have?

Great question. There is no simple answer, but you can possibly identify the fry via the process of elimination. Here’s how:

What species of breeding pairs do you have and what kind of spawners are they (e.g., substrate, cave, open)? Many very young fry won’t venture far from the parents (and/or vice versa). If you have a cave of some kind and the male/female of your pairs is in and out of the cave, the fry won’t be found far from the cave either.

Following up on #1 above, where did you encounter the fry? Normally as I just noted, the fry, especially the newly free swimmers, won’t venture far from the parents or where they hatched. If you keep Rift Lake Africans, especially Lake Tanganyikans, do you have Julies or Shellies? Start there. Obviously, Shellie fry stick close to their shell and will retreat to the shell when startled. Julie fry normally aren’t open area swimmers. They’re most likely going to be “glued” to the underside of rocks (or whatever decorations their parents used to spawn).

What color are the fry? Fry can vary in color and hue. In fact, I can distinguish Julie fry from other fry in my tank, not just from their attachment to the underside of rocks, but also because they’re jet black. My Telmatochromis fry are always cream colored but darken up as they grow. Once you’re familiar with fry of various species, you can use that knowledge to help narrow down the possibilities.